Electrical heater



(No Medel.)

W. MITCHELL.

ELECTRICAL EEATEE. No. 487,285. y Patented Dee. 6, 189.2.

UNITED STATES PATENT OEEICE.'

IVILLIS MITCHELL, OF MALDEN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE gAMERICAN ELECTRIC HEATING COMPANY, OF BOSTON, MASSACHUSETTS.

ELECTRICAL HEATER.

SPECIFICATION forming part of Letters Patent No. 487,285, dated December6,1892.

Applio ation filed March l 5, 18 92.

T all whom, it may concern:

Be it known that I, WILLIS MITCHELL, a citizen of the United States,residing at Malden, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inlillectro-Magnetically Heated Stoves; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable 1o others skilled in the art to which it appertainsto make and use the same.

This invention relates to stoves which are heated by electricity andelectro-magnetic induction. To this end a stove is constructed ofmagnetic material, with cores or studs on which an electric conductor isWound or electric heaters are tted, the said conductor or heaters beingin electric circuit, so that a current passing through it or them willmagnet- 2o ize the said stove. The latter may be applied to heatingrooms, halls, or vehicles, to cooking, steam-generating, or any otherpurpose for which it is suited.

In the accompanying drawings, Figure l 2 5 represents a verticalsectionof an electro-magnetic stove embodying my invention. Fig. 2 representsahorizontal section of the same on the line :c .fr of Fig. I; and Fig. 3represents a detail sectional view of one of the cylindril3o calelectric heaters employed, on a larger scale.

A designates the body of the stove, standing on feet c.. As shown, it isof cylindrical form and upright, but of course may be rectangu- 3 5 larand horizontal or of any other construction which is suitable anddesired. It is o1", magnetic material, preferably iron, and made inseveral sections, secured together by rivets b, that pass throughinwardly-turned iianges 4o B on the side edges of the said sections.

These sections are provided with inwardlyextending studs or cores C, ofmagnetic material, the studs of each section being preferably integraltherewith. On each of these studs is Iitted aheater D, of cylindricalform, similar to that shown and described in my previous patent, No.457,362, and consisting of concentric insulating-cylinders cl,preferably of asbestus, having a Wire E Wound continu- 5o ously thereonto form successive concentric helices, the Wire at each Winding beingpref- Serial No. 425,004. (No model.)

erably in a space about ten times its own breadth, this being found togive the best calorific results. Each heater is protected by a cap orcasing d', and the Wire E passes from heater to heater, connecting thewhole series. Vthen the circuit is closed, the current of electricitythrough the said wire not only heats the said studs and the body of thestove by the heat of resistance,but also magnetizes the said studs orcores and the magnetic body of the stove, so that additional heat, dueto magnetic lag or hysteresis, is produced,especially when analternating or interrupted current is employed.

Of course only a part of the stove may be .made of magnetic metal andprovided with these studs and heaters; but better results will beobtained by the construction shown. By leaving it open at top andbottom, as illustrate'd, I allow the free passage of air, which isheated therein, beside the heating of the surrounding air, due toconduction and radiation. The studs may of course be external, but inthat case will require additional covering or Will be unsightly and inthe way. Therefore the internal studs shown are preferred. It would,however, be more or less difficult to cast the stove as an integral bodywith these inwardly-extending studs and have them all accurate in shapeand position. Therefore the sectional construction is better whenthestove is made of cast-iron. For a Wrought-iron stove the advantage ofsectional construction is even greater. Of course the magnetization maybe effected Without the especial heaters which I have shown; but theseare found to be very convenient and eflicient. Nevertheless, a merewinding of Wire about the studs will be operative if there are studsenough.

A furnace or heater of any size may be made and operated in accordancewith the same principle.

Having thus described my invention,what I claim as new, and desire tosecure by Letters Patent, is-

l. A stove or furnace partly or wholly composed of magnetic material,provided with studs or cores of the same, in combination with Wire Woundon the said studs and conducting electricity, for the purposes setforth.

TOO

2. A stove orfurnace partlygorwhollycom: posed of magnetic material andprovided with studs or cores of the same, in combination with electricheaters applied to the said studs and containing helices, whereby thesaid studs and the magnetic material ofk thestove are magnetized inorder that the said stove may be heated by magnetic lag as Well as byresistance, substantially as set. forth.

3. A stove or furnace partly or Wholly composed of magnetic material andprovided with inwardly-extending studs of the same, in combination withaWire woundthereon and foim1 ing part ot an electric circuit,substantially as set forth.

4. A stove consisting of several sections of magnetic material7 eachsection being provided With flanges for fastening and with in- ,presenceof twowitnesses- WILLIS MITCHELL. Witnesses:

PELATIAH -RJ TRLPP, EDWIN W; PIERCE.

